The vote, which grew out of contract negotiations in the Puget Sound area between Boeing Co. (NYSE: BA) and the union's District Lodge 751, could result in replacement of longtime President Tom Buffenbarger with reformer Jay Cronk.

“If the NLRB throws out the vote that happened Jan. 3, we won’t have to worry about the incumbents coming back on us if they get voted out,” said Les Mullen, president of Local A, which consists of people who assemble aircraft and is the largest of four locals within District Lodge 751. “Our hope is if that vote gets thrown out, at least we’ll be able to bargain in good faith without someone going around us.”

It will be tight, conceded Mullen, who voted for the reform ticket himself.

“It depends upon who you talk to. I’ve talked to people in both camps and they're both optimistic, and they both say it’s not going to be a landslide one way or another,” he said. “No matter which way that goes, we locally need to try to heal and move on and plan for the future ... what’s Boeing going to try to do to us next.”

Tabulation of ballots is to be completed by Saturday, May 10. One monitor from Local 751 will travel to Washington, D.C., to oversee the count, as will representatives from the U.S. Department of Labor.